The information described in this background section is not admitted to be prior art.
Lead-acid batteries produce electricity through the reversible oxidation and reduction of metallic lead and lead dioxide electrodes in ionic contact through an aqueous sulfuric acid-based electrolyte and electrical contact through an external circuit. During battery discharge, metallic lead (Pbo) reacts with hydrogen sulfate (bisulfate) anion (HSO4−) and is oxidized to lead sulfate (PbSO4), thereby releasing hydrogen cations (H+) into the electrolyte and electrons to the external circuit. The lead oxidation half-reaction occurs during battery discharge at negative electrodes (anodes) comprising the metallic lead. During battery discharge, lead dioxide (PbO2) reacts with hydrogen sulfate (bisulfate) anion (HSO4−), hydrogen cations (H+), and electrons from the external circuit, and the lead dioxide is reduced to lead sulfate (PbSO4). The lead dioxide reduction half-reaction occurs during battery discharge at positive electrodes (cathodes) comprising the lead dioxide. Similarly, during battery charge/recharge, the lead sulfate in the anode is reduced to metallic lead, and the lead sulfate in the cathode is oxidized to lead dioxide. The oxidation-reduction reactions that occur at the cathode and anode during battery charge/recharge are driven with energy provided by a voltage/current supply connected through the external circuit.
The performance parameters of lead-acid batteries (e.g., capacity and cycle-life) are largely dependent upon the chemical composition of the constituent materials comprising the electrodes and electrolyte. For example, the charge/discharge/recharge histories of lead-acid batteries affect the capacities and cycle-lives of the batteries, and the effects are quantifiably different between batteries having constituent active materials with different chemical compositions. Additionally, the major aging processes that lead to gradual loss of performance in lead-acid batteries—e.g., anodic corrosion of system components, positive active material degradation and loss of adherence/coherence, and irreversible formation of lead sulfate in the active material (crystallization, sulfation)—are also largely dependent upon the chemical composition of the constituent materials comprising the electrodes and electrolyte.
Accordingly, improved lead-acid battery performance can be achieved through the use of enhanced materials for the production of lead-acid battery components. Consequently, improved materials for the production of lead-acid battery components would be beneficial.